TIANGONG-2 ("Heavenly Palace 2") is a Chinese space laboratory and part of the Project 921-2 space station program. The spacecraft is kicking off a two-year mission to conduct a slate of scientific experiments and lay the technological foundation for a Chinese space station set to be assembled in orbit several hundred miles above Earth by 2022. Tiangong-2 was originally expected to be launched by the China National Space Agency by 2015[8] to replace the prototype module Tiangong-1. Thye mission will demonstrate cargo resupply and propellant refueling procedures required for the country's future space station, and host an array of research experiments developed by Chinese and international scientists. Tiangong-2 measures about 34 feet (10.4 meters) long and 11 feet (3.4 meters) wide. Its two solar array wings will span 60 feet (18.4 meters) tip-to-tip when unfurled in space.